Answer:
The molality of HNO3 is 33.75 molal
Explanation:
Step 1: Data given
mass % of HNO3 = 68 %
Step 2: Calculate masses
If the mass % of HNO3 is 68 %, this means that 68 of 100 grams are HNO3
This means that 100-68 = 32 grams are water.
So mass HNO3 = 68 grams
Mass H2O = 32 grams
mass solution = 100 grams
Step 3: Calculate moles HNO3
Moles HNO3 = mass HNO3 / molar mass HNO3
Moles HNO3 = 68.0 grams / 63.02 g/mol
Moles HNO3 = 1.08 moles
Step 4: Calculate molality
Molality = number of moles HNO3 / mass of water
Molality = 1.08 moles / 0.0320 kg
Molality = 33.75 molal
The molality of HNO3 is 33.75 molal